Characterization of FN-C/H-V, a novel synthetic peptide from fibronectin that promotes rabbit corneal epithelial cell adhesion, spreading, and motility

Purpose. Fibronectin promotes corneal epithelial cell adhesion and motility in vitro and plays an important role in corneal re- epithelialization during corneal wound healing. Multiple domains contribute to the adhesion- and motility-promoting activity of fibronectin. The aim of this study was to identify amino acid sequences that contribute to the rabbit corneal epithelial (RCE) cell adhesion- and motility-promoting activity of the 33 and 66 kD carboxy-terminal heparin-binding fragments of fibronectin. Methods. Synthetic peptides derived from the 33/66 kD fragments of fibronectin were tested for their ability to directly promote RCE cell adhesion, spreading, and motility. To assess the contribution of these peptides to the activity of fibronectin and the 33/66 kD fragments of fibronectin, synthetic peptides, and antibodies against these peptides were tested for their ability to block RCE cell adhesion, spreading, and motility. Results. In this study, we identified a novel peptide sequence derived from the 33/66 kD fragments of fibronectin, FN-C/H-V (WQPPRARI), that directly promotes the adhesion, spreading, and migration of RCE cells in a concentration-dependent manner. A second peptide from the 33/66 kD fragments of fibronectin, FN-C/H-IV (SPPRRARVT), promoted RCE cell adhesion and spreading, but did not promote RCE cell migration. In contrast, two synthetic peptides from the 33/66 kD fragments of fibronectin that were previously shown to promote RCE cell adhesion (FN-C/H-I and FN-C/H-III) did not promote RCE cell spreading or migration. Soluble FN-C/H-V inhibited RCE cell adhesion to surfaces coated with FN-C/H-V, the 33/66 kD fragments of fibronectin, and to fibronectin. In addition, polyclonal anti-FN-C/H-V IgG inhibited RCE cell adhesion to FN-C/H-V, the 33/66 kD fragments of fibronectin, and to fibronectin. Finally, polyclonal anti-FN-C/H-V IgG also inhibited RCE cell haptotactic migration on the 33/66 kD fragments. Conclusions. These data suggest that the amino acid sequence defined by peptide FN-C/H-V contributes to the adhesion-, spreading-, and motility-promoting activity of the 33/66 kD carboxy-terminal heparin-binding fragments of fibronectin. Given the important role of fibronectin in corneal wound healing, these findings provide additional insight into the complex molecular basis of corneal epithelial cell interactions with fibronectin and may be important in the context of corneal wound healing.